Genetics: Longevity Assurance

Researchers have identified numerous longevity genes, variants of which predispose individuals to a longer life span than the average for a species (see Table 1). These gene variants, or alleles, may occur spontaneously in a fraction of the natural population (e.g., human apoE2) or they be created by researchers in laboratory organisms (e.g., mouse p66^shc). A subset of longevity genes extends life span when additional copies are introduced (e.g., worm sir-2, yeast RAS2). The term longevity assurance gene, often used synonymously with longevity gene, should not be confused with premature aging (i.e., progeroid) genes, variants of which apparently accelerate aspects of the aging process (e.g., mouse klotho, human WRN). Longevity genes have been subdivided into two classes. Private longevity genes increase longevity only in certain lineages, populations, or species, whereas public longevity genes are evolutionarily conserved and increase the longevity in a diverse group of species (Martin et al., 1996).